Anodes, either active or powered, or passive (sacrificial) are used to limit, control, and/or prevent galvanic corrosion damage to the tank of water heaters and other metal water vessels. Both passive and active systems protect the tank by being a more active anode than the tank. Passive or sacrificial systems generally use magnesium (Mg) and/or aluminum (Al) rods electrically coupled to the tank. This anode rod is consumed in the process of protecting the tank, hence the use of the term sacrificial. Active systems generally employ a permanent anode rod that typically includes, for example, a titanium alloy. The rod is connected to a power supply which applies the current necessary to null the galvanic effect. Insufficient current provides insufficient protection, excessive current may result in corrosion of other components. Greatly excessive current may result in the production of unacceptable amounts of hydrogen gas. As tank and water conditions vary, the current needed to protect the tank varies. Ideally, the anode current level would be that needed to exactly or substantially null the galvanic effect.
Simple powered anode systems often used a fixed current based on a vessel's size which provided some general level of protection, but could not adjust for varying tank and water conditions. Fixed current systems cannot adjust for tank lining deterioration, various water conditions and other changes over time and installation location.
This Background section is intended to introduce the reader to various aspects of art that may be related to the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.